High availability systems are systems in which many of the processing components (and data paths) are replicated. In the event of a single point of failure in one component, the other component of the pair assumes the tasks of its failed partner. High availability paths therefore provide a measure of security in a system environment without the cost of providing a fully redundant system. However, because the high availability system is not fully redundant, certain resources are shared by the component pairs. It is therefore desirable to identify a straightforward method for controlling access to a shared resource.